CVE-2026-73376 in Ultimate Maps Plugin
Summary
by MITRE • 08/18/2026
Unauthenticated PHP Object Injection in Ultimate Maps by Supsystic < 1.5.0 versions.
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Analysis
by VulDB Data Team • 08/18/2026
The vulnerability identified as an unauthenticated PHP object injection flaw within the Ultimate Maps plugin for WordPress, specifically affecting versions prior to 1.5.0, represents a critical security risk that allows attackers to execute arbitrary code on the target server without requiring valid credentials. This type of vulnerability stems from the improper handling of user-supplied input during the deserialization process in PHP applications. When an application accepts data from external sources and passes it directly into functions such as unserialize() or similar mechanisms, it creates a pathway for malicious actors to inject crafted serialized objects. In the context of Ultimate Maps, this flaw likely exists within one of its administrative endpoints or API handlers that processes map configurations or settings without adequate validation or sanitization checks before deserializing the data.
The technical mechanism behind PHP object injection relies on the existence of "magic methods" such as __destruct(), __wakeup(), or __toString() within classes loaded by the application or its dependencies. If an attacker can control the input passed to a vulnerable function, they can construct a serialized string that instantiates these objects with malicious properties. Upon deserialization, PHP automatically invokes these magic methods, allowing the attacker to trigger unintended side effects. In many cases, this leads to remote code execution because certain classes may interact with file systems, execute system commands via functions like exec() or shell_exec(), or perform database operations that can be manipulated for SQL injection purposes. The absence of authentication requirements significantly lowers the barrier to entry for attackers, enabling anyone on the internet to exploit the flaw simply by sending a specially crafted HTTP request.
The operational impact of this vulnerability is severe and multifaceted. Successful exploitation allows an attacker to gain full control over the compromised web server or application environment. This can lead to the compromise of sensitive data stored within the WordPress database, including user credentials, personal information, and proprietary content associated with the mapped locations. Furthermore, attackers often use such vulnerabilities as a foothold for further lateral movement within the network infrastructure. They may deploy web shells to maintain persistent access, install malware or ransomware, or utilize the compromised server as part of a botnet for distributed denial-of-service attacks. The reputation of the affected website is also at significant risk, as visitors may be redirected to malicious sites or exposed to drive-by download attacks if the attacker modifies frontend files.
Mitigation strategies must address both immediate remediation and long-term security posture improvements. The most effective solution is to upgrade Ultimate Maps to version 1.5.0 or later, where this vulnerability has been patched by implementing proper input validation and restricting deserialization to trusted sources only. For organizations unable to update immediately due to compatibility constraints, temporary mitigations include disabling the specific plugin if it is not essential for business operations. Additionally, deploying a Web Application Firewall can help detect and block requests containing suspicious serialized payloads or known exploit patterns associated with PHP object injection. It is also advisable to review server configurations to ensure that error reporting does not expose stack traces or class names to end users, as this information aids attackers in crafting successful exploits by revealing available classes and their methods.
From a classification perspective, this vulnerability aligns with CWE-502, which denotes Deserialization of Untrusted Data. This category highlights the failure to validate data before passing it into deserialization functions, leading to potential remote code execution or other unintended behaviors. In terms of offensive security frameworks like MITRE ATT&CK, this exploit technique falls under T1059, specifically Command and Scripting Interpreter sub-techniques, as the ultimate goal is often to execute system commands through the injected objects. Understanding these classifications helps in mapping defensive controls more effectively, such as implementing strict allow-lists for deserialization or using serialization libraries that do not support arbitrary object instantiation by default.
Security professionals should also consider conducting a thorough audit of other plugins and themes installed on the WordPress instance, as similar vulnerabilities may exist elsewhere due to common coding practices among developers who reuse code snippets without adequate security reviews. Regular vulnerability scanning and penetration testing are recommended to identify such weaknesses proactively. Furthermore, enforcing principle of least privilege for web server processes can limit the damage caused by successful exploitation, ensuring that even if an attacker gains execution capabilities, their ability to access sensitive system files or modify critical configurations is restricted. Maintaining up-to-date software components remains the most robust defense against evolving threats like PHP object injection attacks.